RETENTION OF PHAGOCYTIC FUNCTIONS IN CRYOPRESERVED HUMAN MONOCYTES

Phagocytosis and respiratory burst activity were measured by flow cyto metry in fresh and cryopreserved human monocytes, after ingestion of E scherichia coli and Staphylococcus aureus. Mononuclear leukocytes, iso lated from 15 healthy donors, were divided into two portions, of which one was examined immediately and the other was cryopreserved for 3 we eks. Morphological characteristics and expression of receptors involve d in phagocytosis were similar in fresh and cryopreserved monocytes. F urthermore, both internalization of bacteria and respiratory burst act ivity remained unchanged after cryopreservation. Transmission electron microscopy confirmed actual internalization of bacteria and not merel y bacterial attachment to monocytes. Monocytes were demonstrated to re tain integral cellular functions during cryopreservation. This may imp ly that the method has potential for use in basal and clinical trials.